A High-Resolution Holocene Ice Core Record of Pacific Climate Variability from the Eclipse Icefield

The North Pacific region including Alaska is rapidly changing, with heat events, summertime drought, and some of the largest wildfire seasons on record, while overall precipitation and extreme precipitation events have been increasing over recent decades. The mechanisms driving recent temperature, precipitation and wildfire changes are different between warm and cold seasons, however existing ice core records from this region do not have sufficient resolution or sensitivity to provide information about summer and winter conditions at human-relevant annual to decadal timescales beyond the last ~200 years. This project will conduct geophysical surveys of the Eclipse Icefield, Saint Elias Mountains, Canada, and in partnership with the Ice Memory Foundation, collect a surface to bedrock ice core with the goal of recovering ice that dates back to the last deglacial transition. The ice core will be used to develop seasonally resolved records of the summer surface temperature history and atmospheric response to past warm periods, which will increase understanding of the sensitivity of this region to extreme temperature, precipitation and wildfire events through time, and improve local preparedness for weather- and fire-related hazards. The Broader Impacts include student engagement and public outreach, collaboration with Kluane First Nation, and ice-core based curriculum development for high school students. This project will conduct geophysical characterization of the Eclipse Icefield, Saint Elias Mountains, Canada, with phase-sensitive radar, terrestrial radar interferometry and multi-offset radar to constrain ice dynamics. The project will recover a surface to bedrock ice core (in partnership with the Ice Memory Foundation), then create a depth-age scale with glaciological flow modeling, stable water isotopes, annual layer counting, stratigraphic tie points to other ice cores, volcanic layers and radiocarbon dating. Past warm periods will be investigated with melt layers. The regional isotope response to deglacial warming will be investigated with water stable isotopes isotope-enabled Community Earth Systems Model iTraCE simulations. The Broader Impacts include student engagement and public outreach, collaboration with Kluane First Nation, and ice-core based curriculum development for high school students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.